Liquid laundry detergents have been known in the art for decades. Modern detergents are often comprised of blends of synthetic anionic, nonionic and cationic surfactants, along with any number of additional ingredients such as builders, water-conditioners, dispersants, soil-release polymers, detersive enzymes and bleaching agents to improve cleaning performance and to achieve performance/cost optimized compositions that are consumer acceptable. Although major strides over decades have moved laundry detergents away from environmentally adverse ingredients such as phosphates, much of the liquid detergents today unfortunately continue to use synthetic surfactants that although biodegradable, pollute nonetheless because they are petroleum derived. Many of the surfactants used today are of petroleum base rather than vegetable or animal sourced, with some surfactants even having biodegradation products that are suspect hormone mimics. Additionally, some solvents, synthetic polymers, chelants, and bleaching agents may also have adverse environmental impact. The art is nearly void of compositions that claim the use of eco-friendly ingredients yet still have suitable performance. Heretofore there have simply been no suitable “across-the-board” substitutions of unfriendly ingredients with eco-friendly ingredients in a laundry detergent composition that can provide consumer acceptable performance at reasonable cost to the manufacturer. It is simple (as shown in the art) to make small substitutions, for example, reduction of builder and/or surfactant levels by increasing enzyme levels, or elimination of phosphates by substitution with other carbonate or bicarbonate builders and biodegradable chelants, but no where is there described the complete replacement of all ingredients in a composition with eco-friendly ingredients to produce an environmentally responsible composition that still provides comparable performance.
One way to increase performance in a laundry detergent and concomitantly reduce pollution is to replace high surfactant and builder levels with high enzyme levels. This strategy is well known in the art, for example US Patent Application Publication US2006/0205628 to Novozymes describes in general terms the “replacement of surfactants, builders, polymers, and bleaches in detergent compositions with enzymes”. However, it is problematic to apply this strategy for the replacement of all pollution-impacting ingredients within a composition, as the required multiple types of enzymes need to be combined and stabilized in ways that heretofore have not been explored, and additional ingredients beyond the enzymes will be needed to make up for lost performance, (e.g. abnormally high levels of optical brightener, or synthetic polymers). For example, when common surfactants are replaced with eco-friendly surfactants, and the highly alkaline builder/chelant systems are eliminated, then simply increasing enzyme level is not enough, and the technology that is truly missing from the art is how to combine the right combinations of different enzymes at the right levels, using the right enzyme stabilizers with the right eco-friendly co-ingredients to boost the performance back to consumer acceptable levels.
Perhaps the best attempt to achieve a multiple-enzyme/surfactant based laundry detergent system is described in U.S. Pat. No. 6,060,441 to Hessel, et al. Unfortunately in this disclosure there are no specifically defined formulations placed into tables. Only design of experiments conducted with wide ranges of each ingredient. However, the '441 Hessel patent does show that a triple combination of surfactants, including fatty alkyl ether sulfate, linear alcohol ethoxylate, and nonionic sugar surfactant (alkyl polyglycoside), are required in combination to successfully stabilize a multi-enzyme formula and to get suitable performance. What is seen from examining the DOE results disclosed in this patent is that linear alcohol ethoxylate is essential to optimized protease, lipase and cellulose activity. Herein we will show this nonionic to not be necessary for enzyme stability.
Incorporating essential oils into detergent compositions is barely known in the laundry detergent context. However, solvent cleaners containing essential oils are well known in institutional and household hard surface cleaning. For example, the popular OrangeGlo® cleaners, marketed by Church & Dwight Co., Inc., are stable micro-emulsions of natural oils such as orange oil in water with surfactants and other ingredients. Patent examples include U.S. Pat. No. 6,407,051 to Smith, et al. that describes emulsifying oils or hydrocarbons such as mineral oil, mineral spirits, pine oil, fatty esters, carboxylic diester oils, motor oils, or triglycerides, and the like into stable water-in-oil micro-emulsions through a combination of alcohol ethoxylate and alkyl polyglycoside surfactant mixtures. The compositions described by Smith can in theory be used for hard surface, laundry cleaning, hand washing, and car washing. These formulas show performance on typical hydrophobic soils derived from petroleum oils or natural fats and oils, and particulate soils such as carbon, common dirt and other soils.
U.S. Pat. No. 6,136,778 to Kamiya describes the incorporation of essential oils into dishwashing detergents at levels where the essential oil contributes a great deal to the overall cleaning performance. The compositions within the Kamiya '778 patent may be used for both manual and mechanical warewashing. For example, Kamiya claims a detergent composition comprising (1) from 0.1% to 20% by weight of one or more essential oils (such as pinene, limonene, geraniol and the like), (2) from 0.25% to 20% by weight of a surfactant (such as N-cocoacyl-L-glutamate and/or coconut diethanolamide), and (3) an enzyme. These compositions would not be effective in laundry applications as the surfactant systems are inappropriate for fabric cleaning.
Additionally, U.S. Pat. No. 6,333,301 also to Kamiya claims a particulate detergent incorporating as much as 10% by weight of terpenes. These high levels of terpene are possible because they are absorbed onto bicarbonate, which has reasonable absorptivity for liquid ingredients. The Kamiya '301 patent does not teach a way to achieve these levels of natural extracts into liquids.
Finally, U.S. Pat. No. 7,033,984 to Hafkamp, et al., and U.S. Pat. No. 7,030,077 to Beers, et al., claim herbal benefit in the laundry through the incorporation of herbal extracts in laundry detergents that deposit the benefit agent onto the clothing that then transfers the benefit agent to the person wearing that clothing. The compositions claimed by Unilever are granular and the herbal agents are incorporated into prilled particles at levels far lower than would provide a performance benefit (for example, aloe at 0.005% by weight). Being these are neither liquid compositions nor using essential oils as performance aids, there is nothing from that art that teaches the present invention to be described below.
A perusal of the prior art demonstrates an absence of ecologically responsible liquid laundry detergents that can maintain consumer desired performance characteristics. In particular the art abounds with enzymatic detergents described over a few decades, most using the same combinations of unfriendly and environmentally suspect ingredients with these enzymes, yet no ultimate accomplishment in arriving at liquid laundry detergent compositions wherein all of the eco-suspect ingredients are gone yet the product still performs at a consumer acceptable level.